Understanding the astrophysical-ice nanostructures formation through classical molecular dynamics

Astrophysical ices (formed by water, among other molecules) act as a catalyst and a reservoir of carbonaceous species, both of which have major implications for astrobiology. In this work, we studied the formation of astrophysical ice nanostructures found in the interstellar medium, having a sheet of graphene as a catalyst substrate, using the classical molecular dynamics technique to model these astrophysical environments. For this, two systems were designed: the first composed of graphene and H2Oand the second composed of graphene, H2Oand CO2. Initially, a simulation box was built where the area was delimited by graphene whose height varied from 4, 6, 8 and 10 nm. The molecules were evenly distributed throughout the box. The molecular dynamics technique proved to be a promising tool to understand the phenomenon of adsorption of molecules on the substrate, allowing us to realize that the random distribution of molecules in the system interferes with the geometric structure formed by an ice nanostructure. This study allows us to understand, from the nanometric point of view, the influence of some physical-chemical parameters, regarding the formation of nanostructures of astrophysical ices, such as the number of hydrogen bonds, the initial size of the simulation box, and its density during the freezing process